摘要
Abstract
When the horizontal layered rock mass tunnels pass through the faulted zones,the construction risks and difficulties were increased due to the rock mass instability caused by weak cohesion and poor mechanical properties.Based on the three-lane,small-clearance twin-bore tunnel project of Wutongshan,a combined approach of 3DEC discrete element numerical simulation and on-site monitoring measurements was applied to systematically analyze the influence patterns of three fault inclinations(60 °,90 °,and 120 °)on rock mass displacement and investigate the engineering application effects of three grouting reinforcement ring thicknesses of 1.5 m,2.0 m,and 2.5 m.The reliability of numerical simulation results was verified through on-site monitoring.Research findings indicate that vertical rock mass displacement concentrates at the top and bottom of the arch,while horizontal displacement clus-ters at the waist and foot of the arch,both symmetrical distributed along the central axis of the tunnel.Rock mass deformation time history curves follow a five-stage evolutionary law of"stabilization-rise-peak-rapid decline-sta-bilization".Different fault dip angles have significant difference of the impact on surrounding rock stability.The de-formation of 90 ° vertical faults surrounding rock was minimal and deformation of 120 ° steeply dipping faults was the most severe;Advance grouting can effectively disperse rock mass deformation.The 2.0 m grouting reinforcement ring got the optimal balance between deformation control and engineering economy,average reduced by 58.06％than the non-grouting scenario of surrounding rock in the tunnel.Field monitoring data revealed that post-grouting vertical displacement of surrounding rock remained within 20 mm,with arch sag convergence remained with in 2.5 mm.The relative error between numerical simulation values and field measurements was ≤5％,validating the reliability of the developed numerical model and the engineering applicability of the advance grouting reinforcement scheme.关键词
水平层状围岩/断层破碎带/围岩稳定性/围岩位移变形/超前注浆加固Key words
Horizontal layered rock mass/faulted fracture zone/rock mass stability/surrounding rock displacement and deformation/advance grouting reinforcement分类
交通工程
